Apparatus for forming and quenching plate springs

ABSTRACT

A spring forming and quenching apparatus in which an array of blocks in sliding contact relationship on a stack of leaf springs is deformed against a stationary member to provide a shaping surface for the hot workpiece which is fed by arms to this surface. A flexible wire, tensioned between a pair of sheaves, retains the workpiece against the surface while quenching liquid is sprayed from nozzles within the blocks and behind the wire against the spring from both sides thereof.

United States Patent Eguchi [54] APPARATUS FOR FORMING AND QUENCHING PLATE SPRINGS [72] Inventor: Shozo Eguchi, 36, 2 Chome, Sakurayama- Cho, Showa-Ku, Nagoya-Shi, Japan 22 Filed: May 1,1969 21] Appl.No.: 820,786

[52] U.S. Cl [51] Int.Cl. ..B21d 7/10,B21d7/16 [58] Field of Search ..29/173; 148/124; 72/364, 397

[56] References Cited UNITED STATES PATENTS 1,362,708 12/1920 La ..148/12.4 2,956,609 10/1960 Shaw, Jr. ..72/252 [is] 3,656,336 [451 Apr. 18, 1972 FOREIGN PATENTS OR APPLICATIONS 525,220 5/1955 Italy ..l48/12A Primary Examiner-Lowell A. Larson Attorney-Karl F. Ross [5 7] ABSTRACT A spring forming and quenching apparatus in which an array of blocks in sliding contact relationship on a stack of leaf springs is deformed against a stationary member to provide a shaping surface for the hot workpiece which is fed by arms to this surface. A flexible wire, tensioned between a pair of sheaves, retains the workpiece against the surface while quenching liquid is sprayed from nozzles within the blocks and behind the wire against the spring from both sides thereof.

2 Claims, 5 Drawing; Figures "PMENTEDAPR 18 I972 V 3, 656 .336

SHEET 1 BF 3 Shozo EGUCHI INVENTOR.

BY {Karl g:

Afiamey I P'A'TENTEDAPR 181912 SHEET 20F 3 ShbzoEGUCi-li APPARATUS FOR FORMING AND QUENCHING PLATE SPRINGS This invention relates to an improved apparatus for forming and quenching plate springs.

In quenching plate springs it was formerly the practice to move a red-hot workpiece along a bending die and force them together through bending rolls and to then throw the bent work into the quenching bath, or to press a work against an arcuate die plate of a predetermined curvature and then place the work thus formed in the quenching tank. Both methods had disadvantages of serious distortion during quenching of the plate springs in unfettered state in the bath, of much labor required for the straightening or relieving, and of deterioration inquality becauseof such an after treatment.

In recent years it has become customary, in order to avoid the distortiondue to quenching, to sandwich a work between a pair of mating dies, move them up and down or rotate them al together, and dip the combination into a bath for quenching. This method precludes the distortion but still has drawbacks in that the'cooling effect achieved by the bath islimited and the quenching time is prolonged accordingly because the plate spring to be hardened is sandwiched between the dies and, moreover, the necessity of moving the press dies renders the construction complicated.

Other major disadvantages presented in common by the conventional methods include the need of much time for the forming of bending dies, arcuate dies or press dies, and the necessity of separate dies for springs of different curvatures, which all add to the cost.

The present invention provides an apparatus of a simplified construction which eliminates the foregoing disadvantages and freely forms springs of many different curvatures with a single die, so that the distortion of springs during quenching can be avoided and the springs can be perfectly hardened within a short time.

For a better understanding of this invention, reference should be made to the accompanying drawing, in which:

FIG. 1 is a top plan view of the essential mechanism of an apparatus for forming and quenching plate springs according to the invention, the right and left halves of the apparatus as divided by a center line, or thelower and upper halves of the apparatus as viewed herein, representing the arrangements of the components before and after the operation of the forming unit, respectively;

FIG. 2 is a side elevational view of the above essential mechanism;

FIG. 3 is an enlarged side view of the feeder unit and associated parts; and

FIG. 4 shows the blocks of quenching unit, FIG. 4-1 being an enlarged side view and FIG. 4-2 a top-plan view.

In the embodiment shown, a plate spring feeder unit mountedon the foremost part of the frame 1 consists of a lateral pair of feed arms 4, 4 adapted to be turned around a horizontal shaft 3 by a feed cylinder 2, a pair of work supports 6,6 adapted to be moved forward and backward by a lateral pair of work supporting cylinders 5, 5', and a work holder 7 which holds awdrkpiece in position. I

In the forming section of the apparatus, the press die consists of a die base 8 composed of a plurality of plate springs of different lengths and a train of blocks 9 arranged in front of the base. The both ends of the press die base 8 are rotatably supported by the front ends of a lateral pair of arms 10, 10 which are adjustable in length. To the middle part on the rear side of the press die base is abutted a threaded rod 11 which is freely rotatable but is unshiftable in position. The other ends of the arms 10, 10 are rotatably supported by the both ends of a die supporting arm 12, which has an opening in the center through which extends the threaded rod 11 in thread engagement therewith.

In FIG. 1, the arm 10is in the position where the die sup- .portingarm 12 has retracted and has bent the die base 8 correspondingly, while the arm 10' is in the position where the die supporting arm 12 has advanced and thereby straightened the die base 8. The reciprocating motion of the piston of a fonning cylinder 13 is conveyed through a driving shaft 14 to a pair of carriages 15, 15' on the left and right end portions of the machine base. The two carriages 15., 15' are synchronously movable to and fro over beds 16,16", respectively, which lie on the machine frame 1. In the same figure, numeral 15 signifies a carriage in the retracted position, and 15' in the advanced position. Between two sheaves 17, 17 which are mounted on the carriages 15, 15 there is extended a forming wire 18. This wire is kept under tension because the sheaves 17, 17' are pulled, in the'direction where the wire 18 is wound, by wire tension cylinders 20, 20' through chains 19, 19.

The quenching section consists of a multiplicity of rear spray nozzles 19 formedin the blocks 9 a multiplicity of front spray nozzles 20 provided diagonally above the rear nozzles, a series of branched oil ducts 21 for supplying coolant under pressure to these nonles, and a main oil duct 22. As better shown in FIGS. 4-1 and 4-2, each block 9 is formed with oil ports 23 and its opening is connected through a threaded connection 24 to each branched oil duct 21. A multiplicity of small openings connected to the oil duct 23 are open sidewise and diagonally frontward, thus defining spray nozzles 19. To attach the blocks 9 to the press diebase 8, a lug 25 formed on the block 9 fits in a small hole formed in the carrier plate of the die base 8, and each block is formed with internally threaded blind holes so that it can be fastened to the carrier plate by bolts.

The operation for forming and quenching plate springs on this apparatus is started with setting of a desired curvature of the die. As the threaded rod 11 is rotated by a motor, the die supporting arm 12 having an internally threaded hole in mesh with the threaded rod 11 is urged forward or backward. Accordingly, the both ends of the press die base 8 rotatably connected through arms 10, 10' with the both ends of the arm 12 also move to or fro, but since the middle part is abutted to the front end of the threaded rod 11, the press die base 8 is caused to alter its curvature. Thus, by suitably choosing the amount of rotation of the threaded rod 11 it is possible to set the curvature of the press die base 8 and therefore the curvature defined by the train of blocks 9 as desired within a desirable practical range.

After the curvature for the press die has been set in this way, the apparatus is switched on for operation, first in the state where the carriages l5, 15' are in the foremost position (the reference numeral 15' indicating a carriage in the starting position). At that time the forming wire 18 is also located in the forward position and is stretched straightly while maintaining a suitable space between itself and the train of blocks 9.

Now if a red-hot plate spring material a is transferred to the feed arms 4, 4' either manually or by a separate automatic feeder coupled to this machine, the feed cylinder 2 works so that the feed arms 4, 4' turn downward around the horizontal shaft 3, together with the workpiece carried thereby. At the same time, the work supporting cylinders 5, 5' move the work supports 6, 6 rearward until the front ends of the feed arms 4, 4' are moved to predetermined points underneath the work supports 6, 6'. The workpiece a is then held, in the narrow space provided between the front end of the work holder 7 and the train of blocks 9, by the work supports 6, 6' and is kept standing on its side as indicated at a.

Feed arms 4, 4 turn further downward to predetermined points where they stop. Then, the forming cylinder 13 is actuated and causes the carriage driving shaft 14 to move the carriage l5, l5 backward, which in turn bring the forming wire 18 between the sheaves 17, 17 on the carriages 15, 15 also backward. As a result, the work a held upright on the work supports 6, 6 is sandwiched between the fonning wire 18 and the train of blocks 9 aligned and attached along the press die base 8.

As the carriages 15, 15 move further rearward, the work a is pressed by the forming wire 18 against the train of blocks 9 and is shaped along the curvature defined by the multiplicity of blocks 9.

On completion of the forming, the plate spring a is quenched as it is by the coolant sprayed simultaneously by the multiplicity of rear spray nozzles 19 formed inside the blocks 9 and by the multiplicity of front spray nozzles 20 provided diagonally thereover. Meanwhile, the work supports 6, 6 are urged by the work cylinders 5, to escape frontwardly from below the work a.

Quenching being over, the forming clinder 13 causes the driving shaft 14 to bring the carriages 15, 15' back to their original positions. This also permits resetting of the forming wire 18.

Consequently, the plate spring a thus formed and quenched is left unsupported and drops down. Upon the return of the carriages 15, 15' to the initial position, the feed cylinder 2 and work supporting cylinders 5, 5 coact to bring the feed arms 4, 4' and work supports 6, 6' back to the starting position. In the meantime, the wire tension cylinders 20, are subjected to a predetermined pressure so as to keep the forming wire 18 under a certain degree of tension.

The operation cycle of the present apparatus has so far been described. In order that changes in the length of work and desired curvature of the plate spring may be met adequately, the beds l6, 16' are movable sidewise for the adjustment of the distance between the carriages 15, 15.

As will be appreciated from the foregoing description, the apparatus according to the present invention has the following advantages:

1. Because setting to any curvature is possible without replacing the press die, a single press die can give plate springs of many different curvatures.

2. The plate spring produced is practically free from distortion due to quenching since the red-hot work just formed is quenched by a coolant sprayed simultaneously from a large number of spray nozzles.

3. The train of blocks altogether serving as a die have builtin spray nozzles, and therefore the side of the work in contact with the die is completely sprayed with the coolant. The opposite side, simply pressed in position by the wire, is also completely sprayed with the coolant from the front nozzles. Thus an outstanding cooling effect is achieved within a short period of quenching.

4. Simultaneous spraying of the coolant by the multiplicity of nozzles ensures uniform cooling of the work throughout which in turn results in a homogeneously hardened structure.

5. The mechanism is simplified because it involves no dipping of the work together with the press die in a quenching bath as in conventional equipment.

With these advantageous features, the invention is novel and epochal as means for forming and quenching plate springs.

lclaim:

1. An apparatus for forming and quenching plate spring workpieces, comprising:

a support frame;

a backing member mounted on said frame;

a stack of elongated leaf springs bearing upon said backing member and extending to opposite sides thereof;

an array of slidingly contacting forming blocks extending along said stack of leaf springs and defining a forming surface, said stack of leaf springs extending over substantially the full length of said array, said blocks being of generally rectangular parallelepipedal configuration and having opposite faces in sliding contact with adjacent blocks on opposite sides thereof, said blocks also being fonned with radiused faces contacting the workpiece;

a threaded spindle extending generally transversely to said stack of leaf springs and lying substantially centrally thereof;

a pair of arms threadedly engaging said spindle and respectively coupled to said stack of leaf springs for drawing same against said member and imparting a predetermined curvature to said surface in dependence upon the degree of rotation of said spindle; a flexible wire overlying said surface and tensionable to retain one of said workpieces thereagainst;

a pair of sheaves joumaled on said frame and respectively engaging opposite ends of said wire, respective chains wound on said sheaves, and fluid-responsive cylinder means connected to drawing said chains for rotating said sheaves and said wire tightly against a workpiece overlying said surface;

actuating means for displacing said sheaves;

first nozzle means spaced from said surface for spraying a quenching liquid on said workpiece while it is held against said surface and onto faces of the workpiece out of contact with said surface; and

second nozzle means formed in said blocks and including passages opening at the junctions of the respective radiused face with the opposite faces of each block for spraying said quenching liquid against a face of said workpiece held against said surface.

2. The apparatus defined in claim 1, further comprising means for automatically feeding a succession of such workpieces into juxtaposition with said surface. 

1. An apparatus for forming and quenching plate spring workpieces, comprising: a support frame; a backing member mounted on said frame; a stack of elongated leaf springs bearing upon said backing member and extending to opposite sides thereof; an array of slidingly contacting forming blocks extending along said stack of leaf springs and defining a forming surface, said stack of leaf springs extending over substantially the full length of said array, said blocks being of generally rectangular parallelepipedal configuration and having opposite faces in sliding contact with adjacent blocks on opposite sides thereof, said blocks also being formed with radiused faces contacting the workpiece; a threaded spindle extending generally transversely to said stack of leaf springs and lying substantially centrally thereof; a pair of arms threadedly engaging said spindle and respectively coupled to said stack of leaf springs for drawing same against said member and imparting a predetermined curvature to said surface in dependence upon the degree of rotation of said spindle; a flexible wire overlying said surface and tensionable to retain one of said workpieces thereagainst; a pair of sheaves journaled on said frame and respectively engaging opposite ends of said wire, respective chains wound on said sheaves, and fluid-responsive cylinder means connected to drawing said chains for rotating said sheaves and said wire tightly against a workpiece overlying said surface; actuating means for displacing said sheaves; first nozzle means spaced from said surface for spraying a quenching liquid on said workpiece while it is held against said surface and onto faces of the workpiece out of contact with said surface; and second nozzle means formed in said blocks and including passages opening at the junctions of the respective radiused face with the opposite faces of each block for spraying said quenching liquid against a face of said workpiece held against said surface.
 2. The apparatus defined in claim 1, further comprising means for automatically feeding a succession of such workpieces into juxtaposition with said surface. 